“Ships have been measuring water temperatures for a long time and are generally used as standards. So the scientists decided to recalibrate the buoy data up to match them. Remember, if you’re measuring absolute temperatures then that gives you the wrong numbers, but not if you’re measuring relative changes. If you add to the cooler temperatures or subtract from the warmer ones you get the same relative change. So it doesn’t matter which way you do it.”
Basically, the scientists are trying to measure change in temperature from a baseline in the mid-20th century, not absolute temperature now. That baseline temperature was measured using water pumped into the ships. It’s not as accurate a measurement of ocean temperature as measuring from a buoy outside the ship, but we don’t need the absolute temperature for this purpose. We want to know how much the temperature has changed, so we have to use the same sort of measurement as the original numbers. It’s just an adjustment of scale, not a falsification of data.
This is what happens when people don’t understand science. They think that scientists are lying for political reasons, rather than politicians lying for political reasons.